Amino-acid Conjugation in Bacteria

Abstract

WE have shown¹ that Arthrobacter simplex is capable of converting cholic acid into 4α-(2-carboxyethyl)-5-oxo-7aβ,γ(R)-dimethyl-3aα-hexahydroindan-1β-butyric acid (I). Our continued interest in defining the intermediates and reaction sequence, involved in the complete oxidation of the cholic acid molecule, has prompted us to investigate the metabolism of the acid (I), A. simplex is not able to utilize (I) as the sole carbon source at a significant rate. It has been found, however, that Corynebacterium equi, cultured in a medium containing (I) as the sole source of carbon, produces a mixture of the conjugates of amino-acids with (I) and the further degradative products of (I) and that one of the conjugates is (IIa), N-[4α-(2-carboxy-ethyl)-5-oxo-7aβ,γ(R)-dimethyl-3aα-hexahydroindan-lβ-butyryl]-L-alanine². Hutzinger and Kosuge³ have described the similar isolation and identification of N^ε-(indole-3-acetyl)-L-lysine formed from indole-3-acetic acid by cultures of Pseudomonas savastanoi.